My invention relates to refrigerator apparatus and more particularly to an evaporator fabricated from sheet metal for use with a mechanical refrigerator.

An object of my invention is to provide a design of evaporator and a method of manufacture whereby the evaporator may be formed of relatively thin gauge material and which will have greater strength and rigidity for a given thickness of metal than evaporators heretofore provided.

member.

It is still another object of my invention to provide an evaporator so constructed that the refrigerant charge required is minimized.

These and other objects are effected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a view in perspective of an evaporator embodying my invention;

Fig. 2 is a IIII of Fig.

sectional view taken along the line 1, showing the manner in which the refrigerant passages in the wall members of the evaporator embodying my invention are formed;-

Fig. 3 is a sectional view taken along the line lIL-III of Fi 1, showing the manner of forming the headers in one of the wall members of the evaporator embodying my invention; and,

Fig. 4 is a sectional view taken along the line IVIV of Fig. 1, showing the method of forming the headers in the other wall member of the evaporator embodying my invention.

Referring specifically to the drawing for a derespectively, which walls chamber l8.

and a bottom connecting wall l6, cooperate to form a refrigerated The function of the evaporator is to change the refrigerant from the liquid phase to the vapor phase and absorb heat in the process of evaporation.

The walls include an inner sheet 26 and an outer sheet 22 formed of metal. The inner and outer sheets plementary corrugations or depressions 24 and 28 and have respectively. corrugations :o and 22 are provided with comrelatively flat portions 26 and 30, between the corrugations. The 28 in the outer sheet 22 project outwardly from the inner sheet 28. The corrugations 24 in the inner sheet 22 project toward the outer sheet 22 so that, when the sheets 28 and 22 are disposed in face-to-face relation, the corrugations 24 nest in the corrugations 28 and form refrigerant-containing passages 32 when the two sheets are fastened together, preferably by welding around their edges and along the flat portions adjacent to the corrugations, as at 25 and 21, respectively.

Refrigerant-collecting headers ,34 and 36 are embodied in-the respective upper ends of the vertical walls l2 and I4, and communicate freely with the refrigerant-containing passages 32. Suction headers 38 and 48 are disposed above the refrigerant-collecting headers 34 and 36, respectively, and communicate with them through the passages 42 and 44, respectively, formed by the sheets 28 and 22. The suction headers 38 and 40 are connected to each other by a cross header 4| through which the vaporized refrigerant which accumulates in the refrigerant collecting header 36 and the suction header 48 flows to the suction header 38. The suction header 38 is provided with a liquid refrigerant inlet 46 and a gaseous refrigerant outlet 48 and is of greater cross sectional area than the headers 34, 36, and so in order to provide a higher vapor space above the liquid level for the vaporized refrigerant.

In order to form the refrigerant-collecting headers 34 and 36, longitudinally extending header portions 56 and 52'with fiat portions 54 adjacent thereto are stamped in the respective upper ends of the outer sheet 22 and complementary header portions 56 and 58 with flat portions 60 adjacent thereto are stamped in the respective upper ends of the inner sheet 26. The header portions 58 and 52 are formed outwardly from the inner sheet 20 and the header portions 54 and 56 in the inner sheet 28 extend toward the outer sheet 22. The header portions 56 and 58 nest within the header portions 58 and 52, respectively, when the sheets 28 and 22 are ,disposed in face-to-face relation and form the refrigerant-collecting headers 34 and 36, respectively, when the sheets 20 and 22 are fastened together, preferably by welding, around their edges and along the flat portions. The refrigerantcollecting headers 34 and 36 are shown in an inclined position but they may assume various so positions without departing from the spirit of my invention.

In forming the suction headers 38 and 46. longitudinally extending header portions 62 and 64 with flat portions 66 adjacent thereto are stamped on the outer sheet 22 and complementary header portions 68 and 10 with fiat portions 12 adjacent thereto are stamped in the inner sheet 20. The header portions 62 and 64 are formed outwardly from the inner sheet 20 and the header portions 68 and 18 extend toward the outer sheet 22. The header portions 68 and 10' nest within the header portions 62 and 6t, respectively, when the sheets 20 and 22 are disposed in faceto-face relation and form the suction headers 38 and when the sheets 20 and 22 are fastened together around their edges and along the flat portions adjacent the headers.

The suction headers 38 and 40 are shown in an;

inclined position but they may assume other positions without departing from the spirit of my invention.

When the refrigerant containing passages 32 andthe headers 34, 36, 38, and M are formed as described above with the header portions and corrugations in the inner sheet 20 nesting within complementary header portions and corrugations in the outer sheet 22, the refrigerant charge required in the evaporator is minimized as the cross sectional area of the refrigerant containing passages 32 and the headers 34, 36, 38, and 68 is less than it would be if the inner sheet were perfectly fiat or if the corrugations and header portions in the inner sheet extended away from the outer sheet. The reduction of the refrigerant charge in the evaporator to a minimum is very desirable in that it reduces the cost of the amount of refrigerant required to charge the refrigerating system. In addition, it improves the safety factor. Furthermore, a more rigid evaporator structure is obtained for a given thickness of material as it is possible to bring the inner sheet 20 and the outer sheet 22 into more intimate contact with each other along the flat portions adjacent the corrugations and header portion and at the meeting points of the complementary header portions and corrugations in the sheets where ruptures are most likely to occur.

. The refrigerated area of the evaporator is increased since the header portions and corrugations in the inner sheet 20 extend within the complementary header portions and corrugations in the outer sheet 22 and thereby subject a greater surface area of the inner sheet 20 to the refrigerating effect of the refrigerant contained inthe refrigerant containing passages 32 and the headers 34, 36, 38, and 60 than would be the case if the inner sheet 20 were fiat. Furthermore, the radius of the corrugations can be enlarged and the space betweer the corrugations lessened without sacrificing strength, thereby increasing the refrigerant contacting area of the evaporator with the air to be cooled.

It will be obvious to those skilled in the art that my invention may assume various forms, such, for example, as causing the depression and corrugations in the outer sheet to extend inwardly toward the inner sheet and nestwithin a similar inwardly extending depression within the inner sheet, without departing from the spirit of my invention. It will also beobvious that the invention may be advantageously applied to the headers and passages separately if so desired.

It will therefore be apparent to those skilled in the art that my invention provides an evaporator in which the refrigerated area is increased, the refrigerant charge minimized and the strength and rigidity of the structure increased for a given thickness of material.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In an evaporator for the vaporization of a vaporizing refrigerant, the combination of inner and outer sheets of metal bent to form a freezing chamber both of said sheets having a series of spaced impressions formed therein, impressed in the same direction and nested one within the other, the impressions in one sheet being more extensive than in the other sheet so as to form passageways for said vaporizing refrigerant, the less extensive impression being curved substantially throughout its length to resist the pressure of the refrigerant in said passageways, portions of the two sheets intervening between the impressions being disposed in abutting relation, and means for fixedly securing the sheets to each other about their edge portions and at said abutting portions.

2. A heat-absorbing element for containing a vaporizing refrigerant embodying first and second wall members disposed in face-to-face relation, an arcuate header portion formed in the first wall member and extending outwardly from the second wall member, a complementary header portion in the second wall member and extending toward the first wall member and nesting in the header portion in the first wall member, a plurality of corrugations formed in the first wall member and extending outwardly from the second wall member, complementary, corrugations in the second wall member extending toward the first wall member and nesting within the corrugations therein, said corrugations opening into the header portion in each wall member, said wall members having substantially fiat portions adjacent the header portions and intervening portions between the corrugations, and means for fastening the sheets together at their edges and along the fiat portions and intervening portions to form a header and passages for containing said vaporizing refrigerant;

3. A heat-absorbing element for containing a vaporizing refrigerant embodying first and second wall members disposed in face-to-face relation, a plurality of header portions formed in the first wall member and extending outwardly from the second wall member, a plurality of complementary header portions in the second wall member extending toward the first wall member and nesting in the header portions in the first wall member, corrugations formed in the first wall member and extending outwardly from the second wall member, complementary corrugations in the second wall member extending toward the first wall member and nesting within the corrugations therein, said corrugations opening into one of said header portions in each wall member, each of said header portions communicating with the other in each wall member, said wall members having flat portions adjacent the header and intermediate the corrugations, and means for fastening the sheets together at their edges and along the flat portions to form a plurality of refrigerant containing headers and refrigerant containing passages.

4. In an evaporator for a vaporizing refrigerant, the combination of first and second metal sheets disposed in face-to-face relation and bent to form a freezing chamber having a side wall and a bottom wall, a plurality of header portions.

second sheet extending toward the first sheet and nesting within the corrugations therein to form refrigerant passages, said corrugations opening into one of said headers, said headers communicating with each other, said sheets having fiat portions adjacent the header portions and intermediate the corrugations and means for fastening the sheets together at their edges and along the fiat portions. r

5. A heat absorbing element containing a vaporizing refrigerant embodying first and second metal sheets disposed in face-to-face relation and bent to form two side walls and a bottom wall of a freezing chamber, a plurality of header portions formed in the first metal sheet in each side wall extending outwardly from said second sheet, a plurality of complementary header portions formed in the second metal sheet in each side wall extending toward the first metal sheet and'nesting with the header portions therein to form refrigerant headers, corrugations in the first metal sheet extending away from said second sheet, complementary corrugations in the second metal sheet extending toward said first sheet and nesting within the corrugations therein to form refrigerant passages, said corrugations opening into one of the headers in each side wall, the headers in each side wall communicating with each other, said sheets having fiat portions adjacent the headers and intermediate the corrugations and means for fastening the sheets together at their edges and along the fiat portions.

6. An evaporator for use in a refrigerating system wherein a refrigerant is successively condensed and evaporated and which evaporator embodies an inlet for liquid refrigerant and an outlet for refrigerant gas, said evaporator embodying first and second sheet metal wall members disposed in face-to-face relation, the first wall member having an impression therein extending outwardly from the second wall member, the second wall member having a complementary impression extending in the same direction as said first-mentioned impression and nested therein, said wall members having fiat portions adjacent the impressions, and means for securing the sheet metal wall members together at their edges and along the fiat portions to form passages for said refrigerant.

7. An evaporator for use in a refrigerating system wherein a refrigerant is successively condensed and evaporated and which evaporator includes an inlet for liquid refrigerant and an outlet for gaseous refrigerant, said evaporator embodying first and second sheet metal wall members "disposed in face-to-face relation, the first wall member having an impression therein extending outwardly from the second wall member, the second wall member having a complementary impression therein extending in the same direction as said first-mentioned impression and nested therein, both of said impressions being general-'- ly arcuate in shape and the impression in the second wall member being shallower than the impression in, the first wall member, said wall members having flat portions adjacent the impressions and means for securing the sheets together at their edges and along the flat portions to provide passages for said refrigerant.